In recent years, as the Internet becomes widespread and memory media have an improved performance and decrease in cost, a content distribution system which writes a large volume of content, such as music data and program data, into a memory medium, and distributes it to a user, and which enables the user to acquire a key which is given as access to use the content stored in the memory medium from a server for exclusive use via communications by connecting with the server via the Internet is used.
As such a content distribution system, for example, patent reference 1 discloses a content distribution system which supports mobile terminal players. The content distribution system disclosed by this patent reference 1 is comprised of a content provider equipped with a content server and a user information data base including user's downloaded information and right information data, for distributing a content according to a check-in check-out rule of SDMI via a communication network, and a user's mobile terminal player having a recording medium playback function of playing back a content downloaded to a recording medium, and a check-in function of returning the right to be able to play back a content to the content provider. In the case of distributing a content to the mobile terminal player, the content provider manages the number of times of check-out of the content to the user, when the user checks in the content distributed, the mobile terminal player performs content distribution management in such a way as to erase an encryption key for playback of the content and the registration of the file name.
[Patent reference 1] JP,2002-83152,A
Because the content distribution system disclosed by above-mentioned patent reference 1 is constructed in such a way as to carry out, via communications, acquisition and return of a key which is given as access to use a content from and to a content provider which performs management of content distribution, the content distribution system is based on the premise that equipment using the content has a communication function. Therefore, equipment which cannot use the communication function cannot use such a content distribution system.
Hereafter, application of a content distribution system as mentioned above to a car navigation apparatus is considered. Although most of recently-developed car navigation apparatuses have a communication function, many car navigation apparatuses use a mobile phone as a communications means. However, because there is a large difference in periods of use (use cycles) between mobile phones and car navigation apparatuses, there is a case in which, when. a user buys a new mobile phone, the user cannot use his or her new mobile phone as the communications means of his or her car navigation apparatus. Furthermore, there are cases in which a cable for exclusive use is required for connection between a mobile phone and a car navigation apparatus, and therefore some users do not use the communication functions of their car navigation apparatuses. Therefore, under present circumstances, a problem is that it is difficult to apply a content distribution system as mentioned above to a car navigation apparatus, just as it is.
The present invention is made to solve the above-mentioned problem, and it is therefore an object of the present invention is to provide a content distribution system which safely distributes a key to a terminal having no communication function so as to enable the terminal to use a content, the terminal, and a server.